(a) Technical Field
The present disclosure relates to an auxiliary fuel tank for a flexible fuel vehicle, and more particularly, to an auxiliary fuel tank for a flexible fuel vehicle that reduces the manufacturing cost and weight of a vehicle by obviating a venting line which passes through an engine compartment and an underbody of a rear floor.
(b) Background Art
Many vehicles currently being developed are flexible fuel vehicles (FFVs) using ethanol, the main material of which is sugar cane, as a fuel. Ethanol has not been practically used as a fuel of vehicles due to high corrosiveness and fuel system corroded by water contained the ethanol. However, the use of ethanol has increasing researched due to an increase in international oil prices and environmental issues such as exhaust gas regulations, and laws related to the use of fuel containing ethanol for vehicles have been enacted in various countries.
Since ethanol has a higher octane number than gasoline, ethanol vehicles are more powerful than gasoline vehicles but are inefficient due to the low calorific value of ethanol. In addition, since ethanol has a low explosion point, ethanol vehicles may not start normally at temperatures equal to or less than a particular temperature (e.g., about 16° C. to 18° C.). Accordingly, a flexible fuel vehicle using ethanol as a fuel includes an auxiliary fuel tank for storing gasoline fuel to improve the ease of startup during the winter season or colder weather temperatures. The auxiliary fuel tank is mainly installed in an engine compartment in consideration of the ease of injection of gasoline fuel. The pressure in the auxiliary fuel tank installed in the engine compartment may be increased due to the temperature of the engine room. Accordingly, fuel evaporation gas (HC) harmful to the human body may leak out of the auxiliary fuel tank and enter the vehicle interior.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.